Control for change-speed mechanisms



.June 19, 1951 B, souLE EIAL CONTROL FOR CHANGE SPEED MECHANISMS Filed June 29, 1948 2 Sheets-Sheet 2 INVENTORS ATTURNL'Y Patented June 19, i951 CONTROL FOR GHANGE-SPEED MECHANISMS Harold B. Sou'le, Barrington, and Gordon W.

Smithson, Pawtucket, R. I., assignors to Niles- Bement-Pond Company, West Hartford, Conn, a corporation of New Jersey Application June 29, 1948, Serial No. 35,808

8 Claims. 1

This invention relates to an improved control means for change speed mechanism and more particularly relates to means for changing or shipping the speeds of an automatic turret lathe.

In automatic turret lathes the tool or turretslide feed and spindle speed shipping is usually automatically controlled by dogs on a rotating dog drum or other part or parts driven by the machine which has relatively very slow motion, thus making it impossible, in a practical manner, to increase or decrease the speed of the spindle or the feed or tool slide while the tools are cutting the workpiece.

The principal object, therefore, of this invention is to provide a speed change mechanism and control means therefor, which will have general application, but when applied to machinetools permits the changing of speed while the feeding or cutting movements of the slide or slides of the machine is taking place, and permits this change of speeds under the control of the dog drum of the machine or manually while the dog drum is rotating very slowly, and permits of increasing or reducing the speed while the Work on the spindle head is being cut or is being otherwise operated upon by the tools; and, furthermore, permits of establishing changes of speeds of very short duration or of as long duration as desired.

More specifically the objects of this invention embrace the provision of electro-pneumatic meansincluding a shiftable member for shifting clutches of a change speed mechanism wherein, whenever said member has been shifted to a predetermined position to change the adjustment of a coupling or clutch of the change speed mechanism, the air pressure is relieved, thus reducing wear and friction of the connecting parts and minimizing heating of the parts and extending their service life.

Another object of this invention is to provide control mechanism for change speed mechanism, of the character above mentioned, and incorporating safety cut-out devices which operate automatically to stop the machine whenever the control mechanism has failed within a preestablished period of time to properly complete an attempted engagement of a coupling or clutch of the change speed mechanism, and thus preventing the wear, friction, heat and damage to the coupling or the burning out of the clutch plates which otherwise would tend to take plac e.

A further object of this invention is to provide an clectro-pneumatic control for change speed mechanisms and which control is simple, light, or i delicate in its functional operation yet durable and of small size, and is convenient to install, in a machine, and one which is quick, positive and reliable in response and in operation.

All the objects of this invention will be in part obvious and in part pointed out hereinafter.

In accordance with the objects of the present invention, said invention is concerned particularly with means for moving a throw lever (or equivalent part) of a clutch or clutches whereby either clutch may be engaged selectively or both clutches may be disengaged, and wherein said throw lever is shifted by means of a piston connected to the throw lever and displaced by means of pressure through the agency of solenoid operated valves which are controlled by electrical switches and circuits which are preferably under the control of switch operating dogs on the dog drum of the lathe, or which may be arranged to be operated manually. This arrangement is such that, during normal operation of the machine, the dogs selectively operate one of a series of switches, and the circuits thereof being such, that, when one of these switches is operated by one of the dogs, a circuit will be established which will energize one of the solenoid valves to admit pressure to one side of the piston and cause the throw lever to be shifted in one direction to engage one of the clutches. Similar actuation of another of said switches establishes a circuit which energizes a second solenoid valve to admit pressure to the other side of the piston and cause said throw lever, or another throw lever, to be shifted to engage the other clutch. Means are provided in the circuits whereby, in the event that the throw lever has not been shifted sufficiently to properly complete the attempted engagement of one of the clutches, after a certain predetermined length of time, the power source or a driving motor (which drives the change speed mechanism) will be broken and the machine will be stopped. Also, actuation of still another, at least, of said switches, either by dog drum or by hand, will reset the control of the present invention to allow the machine to be started, after having been stopped as just stated; and this same actuation of said switch will cause said clutches to be disengaged. Moreover, the arrangement is such that, when a clutch is properly engaged, whether or not a clutch controlling dog on the dog drum has released its switch, the circuit will be broken to the energized solenoid valve and the pressure will be relieved while the clutch is still -in mesh with medium speed gear L1 tures of construction, arrangement of parts, combinations of elements and methods of operation which will be pointed out hereinafter and the scope of the application of which will be set forth in the claims that follow.

In order that a clearer understanding of this invention may be had attention is hereby directed to the accompanying drawings forming a partef this application illustrating certain possible embodiments of this invention and in which Figure l is a sectional view through the headstock of a turret lathe illustratinga change speed mechanism to which the control mechanism of this invention may be applied;

Figure 2 is an enlarged sectional fragment of the overrunning gear and is taken on line 2-2 of Fig. 1;

Figure 3 is a diagrammatic or schematic view of the electro-pneumatio clutch control mech anism and electrical circuitsassociated therewith,

and shows the air cylinder in section and a portion of the change speed mechanism of the lathe, and also a representation of an associated timer device; and

Figure 4 is a Side view partly in section :of one of the solenoid operated air valves.

Similar reference characters refer to similar parts throughout the several views of the drawings.

Referring to the drawings, the change spec mechanism shown includes a driving shaft 5 on which are keyed a low speed gear .3 l, amediuin speed gear E2 and a high speed gear 13. Shaft l also has a driving pulley M whereby the shaft may be driven .by a suitable motor indicated diagrammatically in Fig. 3 at M. Another shaft l has keyed to it a gear .58 of the overrunning type well known in the art; but for clarity it may be stated that, with reference to 'Fig. 2, the gear it has an inner sleeve ida keyed to the shaft f5 and fixed to an inner circumference of the gear are circumferentially spaced tapering wedge members i? and formingwith the sleeve Ilia circumferentially tapering slots Na in which are seated rollers i5 which are normally pressed by means of springs 55? toward the smaller end of the slots, the socket type follower so being interposed between each roller and spring and the part ifib being a hardened wear ring fixed on the sleeve Mia. Thus, when gear l-S is rotating in the direction of the arrow applied to Figure 2, the rollers 1% become wedged in the slot between the members it and the wear ring Ifib on sleeve Ilia and shaft 45 rotates with gear 16. On the other hand, when shaft l5 tends to rotate in the direction of the arrow faster than gear It, the engagement of the shaft H with rollers [8 will move the rollers toward the wider end of the slot against the tension of the springs 29 and thus shaft i5 is released to rotate in the direction of the arrow relatively to and faster than gear 16. Gear it is in constant mesh with low speed gear II and continues to rotate wheshaft 85 is rotating at its intermediate or high speed.

Rotatable on shaft I5 are a gear 22, which is [2, and a gear 23, which is in mesh with high speed gear i3. Also the shaft 45 has a gear 2d keyed thereto and through which power is taken off of shaft i5 as by a gear keyed to a shaft 26 which also has. another gear El keyed thereto which meshes with a gear 28 on a shaft 253 having another gear keyed thereto and which meshes with a gear fixed on the spindle S2. A gear 33 meshing with a gear 3% keyed on shaft 26 takes power from end of cylinder assvgsee 4 shaft 26 to drive the feed shafts (not shown) that actuate the turret slide 5?, cross-slides 48 (Fig. 1) and the dog drum or wheel Hid (Fig. 3), the connections to which parts not being shown. On shaft i5 between the gears 22 and 23 is keyed a clutch sleeve, cone sliding part 35 disposed between double clutches 3E and 3'! rotatable on the shaft !5 so as to alternately engage one of said clutches and disengage the other or assume a neutral position disengaging both. The

clutches 36 and 3? are fixed, respectively, to gears 22 and23 to rotate therewith. Intermediate the clutch sleeve 35 is a circumferential channel track 38 .in which rides a shoe 39 having outwardly extending diametrically opposite projections 49 that areengaged by the arms of a yoke 4| formed on thelower end of a clutch throw lever 43 which is keyed to and supported by a shaft 54, which may be oscillated by a hand-lever l-2 (dotted lines Fig. 3) to actuate the clutch-sleeve 35.

When throw'lever 43 is in its central'or neutral position, as shown, neither of the clutches 3B or 37 is engaged and therefor shaft hi and,-con sequently, spindle '32 are driven at low speed through gears H and 22. When throw lever43 is shifted to move sleeve 35 to the left, clutch 35 becomes engaged and clutch 37 remains disengaged, which establishes a medium speed drivlng connection between gear l2 and shaft l5 through gear 22, clutch 36 and sleeve 35. When the throw lever 33 is shifted from neutral position to the right, clutch 3? becomes engaged and clutch 25 remains disengaged and a high speed driving connection is established between gear 53 and shaft !5 through gear 23, clutch 37 and sleeve 35. .Shaft l5 over-runs gear IE when these clutches are connected in the manner explained above. The clutches are held in engagement and. the clutch sleeve or cone 35 is held in its neutral position by a yieldable dent D mounted on a fixed part of the machine and selectively engages in V-shaped notches spaced about a brushing, segment or other suitable part D fast to and rotatable with the throw-lever shaft M.

In the drawings the head of the spindle 32 is shown as carrying a chuck 35 and there is also indicated schematically a turret 5, a turret slide 3? and a cross slide 48, all mounted on the bed or base 49 of the lathe.

The above described spindle drive is old in the art and is referred to for an understanding of the present invention wherein the clutch shifting or shipping mechanism is pneumatically operated and controlled in the manner now to be explained.

This pneumatic means for shifting a clutch or clutches through'lever :53 includes an air cylinder supported in any suitable manner and in any suitable location on the machine "or base of the lathe. Within the air cylinder is a piston head 5! from which an elongated piston rod 52 extends through a suitable bore 53a provided therefor in a block 53 which extends from one Beyond the block '53, the piston rod 52 is connected to throw lever 43 so that shifting of piston rod 52 will shift the throw lever 53 in the same directions. For purposes of the present illustration, the piston rod 52 has a pin 55 that projects into a notch or bifurcation 5 rd in an armed fast on the shaft M to 'fnich the throw-lever G3 is fast. Piston rod '52 extends beyond throw lever 351, as at 520: and there is provided with a bracket 56 carrying a pair of spaced adjustable set screws 5'! and 58 for a purpose which will be explained hereinafter.

The piston is reciprocated in the cylinder by air pressure delivered from a suitable source, indicated at 66, and from which a conduit 6I leads to two (2) solenoid valves 62 and 63. An air pipe 64 leads from valve 62 to the cylinder at one side of the piston head 5I and an air pipe 65 leads from valve 63 to the cylinder at the opposite side of piston head 5|.

Each of these valves 62 and 63 comprises an elongated casing (see Fig. 4) having an opening in its lower end which receives a threaded nipple on the main air supply line 6|. The interior of the valve casing c is divided by a partition 11 having a bore b therein longitudinally of the casin and at the ends of the bore are provided valve seats d and e. A plunger 1 reciprocates in and is of less diameter than said bore and has a valve it fast thereon to cooperate with the seat d and has on its other end a valve e slidable thereon and normally held against the seat 6 by a spring the valve e being opened by the plunger F, when contacted by the shoulder f in its downward movement moving it against the bias of the spring 9, and allows air-pressure to flow from supply line 6|, past valve seat e to outlet port 0. There is an exhaust port h in the side of the casing above the valve d. top of the valve and the plunger s thereof depresses the plunger 1, when the solenoid is energized, and raises it to full line position, when the solenoid is de-energized.

An electrical control means is provided for operating these solenoid valves to move the piston to predetermined positions in its cylinder 50 and thus to adjust the clutches 36 and 31 accordingly. As part of this control the portion of the piston 52, which is disposed within the ton head 5| or the neutral position of the clutchsleeve 35. The length of the portions 66 and 61 corresponds to the movement of the pistonhead 5! from neutral position, in either direction, to fully engage either clutch 36 or 31 and,

as shown, the length of portions 66 and 61 are about equal. The portions 69 and I6 of the rod 52 are of less diameter than the diameter of the portions 66 and 6'! and are of a width or length axially of the piston rod 52 so that plungers I2, I3 and I4 will not be depressed thereby. Both end walls of the portions 66 and 61 are beveled as at II. The three (3) 'plungers I2, I3 and I4 are disposed in three (3) recesses I5, 76 and 11 formed in the interior of the block and in axial alignment with the rod 52 and opening into the bore 53a and are individually biased to move into the bore by springs I8 which are positioned between the rear faces of the plungers of the interior wall of the recesses. These plungers are so positioned relatively to the enlarged portions 66 and 61 of the piston rod that, when the piston head 5| is at the center of the cylinder 56 and the clutch-sleeve 35 is in its neutral position, the plungers project into the bore with the The solenoid s is mounted on the conical head of plunger 12 resting against the outer beveled end of portion 66 which is at the groove 69 and with the conical head of plunger I3 seating against the adjacent beveled ends of portions 66 and 61 at the groove 68 and with the conical head of the plunger I4 resting against the outer beveled end of portion 67 at groove I6. In this position of the piston the throw lever 43 (and the hand-lever E2) of the clutches will be in neutral position and neither clutch 36 or 31 will be engaged.

A switch stem 86, having a switch contact element BI, extends through a suitable bore in the block 53 and is fixed to plunger I2 and a similar switch stem 82 having switch contact 83 extends through a bore in block 53 and is fixed to plunger I4. When the piston is shifted from central position to the left, portion 66 of the piston rod moving under plunger I2 elevates this plunger and closes the switch 6| and, since the reduced portion I6 of the piston rod 52 moves under plunger I4, this plunger is not raised. On the other hand, when the piston is moved from central position to the right, enlarged portion 6'! of the piston rod passes under plunger 14 raising this plunger and closing switch 62, but groove 63 of the piston rod is sufficiently wide so that during this movement the reduced portion 66 remains under plunger 12 and this plunger is not raised. Plunger I3 serves merely as a detent to aid in restraining inadvertent displacement of the piston rod and to aid in holding the piston rod in central or neutral position.

As shown, the circuits which control the operation of the solenoid valves 62 and 63, and, consequently the air piston EI and thereby the speed change settings of the change speed mechanism, are under the control of three dogs I6!, I62 and I63 carried on the rotatable dog drum, wheel or other movable parts of the lathe and which is indicated at I64 (Fig. 3). Dogs I6I and I62 are adapted respectively to close normally open switches I65 and I66 at predetermined times in accordance with the placement of these dogs on the dog drum. Dog I 63 operates a switch I61 to close one circuit between its normally open terminals I68 and I 69 and to break another circuit between normally closed terminals I68 and H6.

When the air piston rod 52 has been moved a sufiicient extent to the right from its neutral position to properly engage clutch 31, the set screw 5'1 on bracket 56, carried on piston rod 52, has moved sufiiciently to engage and move a pivoted switch lever III to open a normally closed switch H2 and, when the piston rod 52 has been moved a suiiicient extent to the left to properly close clutch 36, the set screw 58 carried on the bracket 56 has moved sufficiently to engage and move the pivoted switch lever II3 to open normally closed switch I I 4. Either switch I I2 and H4 remaining closed unless and until the piston rod 52 has been shifted a suificient distance in one direction or the other to properly close one of the clutches 36 or 31.

The control circuit for the solenoid valves also includes an electrically triggered timer T which may be any one of a number now available on the market, the particular type or construction not being important but should be such that it is started by the closing of a circuit thereto and, after running for the time for which it has been pre-set, it will act to operate an element, such as an electrical switch, controlled by the timer, and further should be such that, should the current to the timer be broken before the timer has completed its time cycle, the timer will stop and will reset itself without acting to operate the element controlled by the timer. When the circuit to the timer, therefore, is closed again the timer will start again to run for its 'complete time period before acting,

To present a general indication of such a timer "and how it is included in the change speed control circuits, there is shown in Fig. 3 of the drawings a timer witha casing I having secured thereto a bracket I2I to which a block I22 is connected by swinging arms I23 for vertical reciprocation beneath the casing. A spring I24 compressed between the casing I20 and the top of block I22 exerts downward pressure on the block. Beneath block I22 a vertically swinging armature 125 of an electromagnet I26 is pivoted on a bracket I21 and a tension spring I28 connected to casing I26 and armature I exerts upward pull on the armature. The force of spring I28 is stronger than the force of spring I24. An upwardly extending post I29 on armature I25 is in the path of movement of block I22 and not only determines the limit of downward movement of block I22 but also moves block I22 upwardly, when the armature I25 is raised by spring I28, while block I22 is resting on post I29, When magnet I26 is energized, it draws armature I25 and its post I29 downward against the opposition of springs I28, thus relieving block |2-2 from theupward pull of spring I23 and allowing block I22 to be moved downwardly by the force of spring I22. However, a finger I32; secured to block I22 and extending into casing I23, is connected to some suitable dashpot arrangement, or other movement retarding means within the casing, such as the diaphragm Iilfia, which determines and controls the rate of downward movement of block I22, when free of post I29, A finger I3I on block I22 is in engagement with a spring terminal finger I32 of a switch I33. When armature I25 is in its elevated position (as shown) holding block I22 elevated, switch IE3 is open. Energizing the magnet I26 will draw armature I25 down and, when block I22 has been moved down a predetermined "distance by spring I24, it will close the switch terminal I32 of the spring switch linger I22 against the other terminal I35 of the switch I83, thus closing the switch. Should magnet I22 beco'me-deenergi'zed before block I22 has moved a su'liicient distance downwardly to close switch I33, the armature and the block I22 will immediately be raised by the force of spring I28 to their initial starting position. The time cycle of the timer is the time it takes for the block I22 to move downwardly under the restraint of the retarding means I362! from initial starting position to switch I33 closing position. The time obviously is adjustable by adjusting the rate of downward movement of block I22 or the extent of movement between starting and switch closing elevations, or both. The timer just described is one of a type known "on the market as Type R Timer of the Square D Company, but any suitable timer of the same 'or substantially the same function may be employed, as, for instance, as another example, a tixiier relay of the electronic type.

The spindle drive motor is designated M in Fig. 3 of the drawings, Motor M drives the shaft III of the change-speed mechanism by means of a suitable driving connection (not shown) between shaft II].

8 the motor shkaft and the pulley I4 (Fig 1) on The power supply lines are indicated A and B and the spindle motor M is in lines B and C, line C being connected with line A through a conductor 290 which leads to a normally closed switch lti3l and from thence to a conductor 2M connected with line C. An electrical spindle motor control is generally indicated in the line C and designated SC and includes start, stop and jog push-button switches, indicated by ST SP and J, respectively; and the other side of the motor is connected to power line B by conductor 202. V

Switch -i-@I3I is included in the clutch shifting control circuits and it is apparent that this switch opens and closes the power circuit to the motor M and is provided for safety and protective purposes as will become apparent hereinafter.

v Figure 3 illustrates the setting of the parts and the conditions of the circuits whenthe clutches 3d and 37 are disengaged or, in accordance with the present illustration, when the spindle of the lathe is being driven at low speed by shaft I5 and through the over-running gear It; and in this setting the head 5! of the air piston is in its intermediate or neutral position in air cylinder the clutch throw lever 23 is in its intermediate or neutral position, and spindle motor control switch liiill is closed. The circuitsare not closed to either of the solenoids of solenoid valves 82 or $3 or to the magnet I26 of the timer T referred to above. V v

The change-speed mechanism is automatically shifted to drive the spindle at high speed upon the closing of switch I85 manually or by the dog IilI provided on dog drum I534 for the purpose, or may be 'shiftedto establish medium speed spindle rotation by the closing of switch I96 manually or by the dog I22 on dog drum I02, and said mechanism can be restored to neutral position, as in the present case, for low speed rotation from either medium or high speed position by operating switch It? manually orby dog I23. of dog drum IIE I. The switches I85, I26 and IilI may be manually operated by finger-liftrods or levers interposed between the dog drum and the switch stems, as generally indicated at Z.

Therefore, closing speed switch I25 completes a circuit fromv power line A through conductor 2%, switch tilt-I and conductors 2215a, 20 5b and 2250 toswitch I65 and therefrom through conductor 2233, switch H2, conductor 28?, relay 3% and conductors 228a and 208 to power line B. Relay 326, when energized, closes an interlock or holding switch 322- 4 thereby connecting conductors 265a and 229 establishing a holding circuit for relay 326, the current passing from line A through conductor 2229, switch Mil-4, conductor 2259;, switch 358-4, conductor 2ll9, n r l o e s itch I 2 con u t r 5. relay 322 and conductors 268a and 268 to power line B. Energizing relay 363 also closes a second switch 388-2 thus energiiz ng the solenoid o f solenioid air valve E52, the current passing from power line A through conductor 2%, switch IIl0I, conductor 205a, switch 3fill, conductor 225a, switch 392-2, and conductor 2H) to the solenoid of valve 62 and thence through conductors 208d, 2280, 262i) and 268a, and 268 to power line B. Energizing relay 3% also closes a third switch 32t3 which closes a circuit to the magnet I26 of the timer above referred to, the current passing from the line A, conductors 222, 223 and 2 I2 through switch 3Ii Il3 and conductor 2I3 through the magnet coil I26 to the conductor 2 I4 9 to line B. This starts the timer running by drawing the magnet armature I and its post I29 downwardly from the timer block I22 and allows the spring I24 to start moving block I22 downwardly at the speed permitted by the retarding device I 33a provided in the casing I255.

The energizing oi the solenoid of valve 62 causes air to be delivered through conduit 64 to the left hand side (in Fig. 8) of piston head 5| and displaces piston rod 52 to the right, whereupon the enlarged portion 61 of the piston rod 52 moves under the plunger I4 and raises the stem 82 of switch 83 to close it. This conditions a circuit which will cause the air cylinder and throw-lever 43 to be returned to neutral or clutch disengaging position upon the throwing of switch I07 from terminal IIii to its terminal I99 as will be more fully described hereinafter. As a result of the above operation, if piston rod 52 has moved a sufficient distance to the right to cause clutch 3! to be properly engaged, the set screw 57 on the bracket 55 carried on piston rod 52 will have moved a suflicient distance to open the switch H2 to de-energize relay 369 and this, in turn, causes its interlock switches see-1, 3 .3S2 and 300-3 to open. Opening of relay switch 3l03 breaks the circuit to the timer T and the timer resets itself to initial starting position in the manner above stated. Opening of relay switch 309-2 breaks the circuit to the solenoid of valve 62 and effects the release of air pressure from the air cylinder 56 through exhaust port h. The opening of relay switch 3lliiI breaks the holding circuit that was previously established through relay 3%. The clutch 31 is now engaged and the piston 5| is at right-hand end of cylinder 50, from which positions they may be operated b admitting air from pipe 65 to the righthand side of piston 5I by closing speed switch I06 that will cause clutch 31' to be disengaged and clutch 36 engaged, or by closing contacts I08 and H9 of neutral switch Ill'i to disengage both clutches and 37, as will be later explained.

It will be noted, however, that set screw 51 is so adjusted on piston rod 52 that unless the rod 52 is shifted far enough to establish the proper engagement of clutch 31, switch II2 will not be opened thereby and the circuit to the timer magnet I26 will not become broken because relay 3% will remain energized. In such event, the timer T will continue to run and, after running for the pre-determined time for which it is set (which is usually sufficient to allow for the operation of the engagement of the clutches), it will close the switch I33. The closing of switch I33 of timer T establishes a circuit through a safety relay 408, the current passing from power line A through conductors 209 and 203 to terminal I35 of switch I33 and from terminal E34 of this switch through conductor 2I5 through relay B and conductor 208 to power line B. The energizing of relay 460 opens the motor control switch Mill-I and causes the motor M to stop. Energizing relay 406 also closes an interlock or holding switch 4IJO2 which maintains a holding circuit through the relay the current passing from power line A through conductors 200 and 204 to the terminal I08 of neutral switch Iii! and thence from the terminal I I!) of this switch through conductor 2 I 6, through switch 4i (l2, conductor 2 I5, relay 409 and conductor 298 to the other power line B. Now, the spindle motor M-and in most cases where it is contemplated using this invention the entire machine is stopped--can only be restarted by deenergizing relay A85 to reset or close normally closed interlock switch 4ilIlI.

The restarting of the machine or motor M can be, accomplished manually by operating fingerlift lever Zof neutral and resetting switch Ifi'i or by dog 583 of the dog drum Hi4, as, when handcranking, to move neutral switch I E from its contact lit to close switch contact is which breaks the circuit to relay see and deenergizing thus causing the motor circuit control switch to close re-establishing the circuit to the motor M and causing said relay holding switch 4 l@2 to open. Closing of switch it? on contact its energizes the solenoid of air valve 53, the current passing from power line A through conductors 232 and 29 i to terminal 5 35 of neutral switch iii! and from its terminal i953 through conductor 152:), through closed conditioning switch 83, conductor 229a. to the solencid of valve 63 and from thence through conductors 2950, 298b, 208a and Edi! to the other power line B. Energizing the solenoid of valve 63 causes air under pressure to flow through air conduit 65 to the right hand side of the piston head 5i and moves the piston rod 52 to the left. When the piston rod has arrived at neutral position the plunger l4 rides oil the enlargement S! of the piston rod into the reduced portion ii and thereby moves inwardly opening switch 33, thus breaking the circuit to the solenoid of air valve 63, whereupon the valve becomes adjusted to relieve the right hand side of piston head 55 of the air pressure by exhausting through exhaust port it and the piston rod, the clutch sleeve 35 and throw lever 43 stop in neutral positions.

The operation for adjusting the speed of the change-speed mechanism to medium speed is similar to that, which has been described, for adjusting the speed mechanism to high speed, except that the medium speed adjustment involves speed switch i556, which may be closed manually or by dog E2 on the dog drum Hi4, and also involves relay 5%, the conditioning switch II4 controlled by switch lever II3 actuated by set screw 58 on the piston rod bracket 56, the piston rod actuated switch 89 and the energizing of the solenoid of air valve $3 to move the piston rod 52 to the left for shifting the throw lever 43 to the left and thereby to engage clutch 36, meanwhile closing switch 8%; Relay 599 is energized for the same purposes as is the high speed relay.

The circuit which energizes relay 53!), when speed switch IE6 is closed, now includes power line A, conductor 2653, switch Mill-I, conductors 285a, 285b, 2%50 and 285d to switch I86 and, from this switch, conductor 22I, switch I I4, conductor Zlla to a relay 5% and, thence, through conductors 2i8b, 268a and 253 to the other power line B. Energizing relay 509 closes an interlock switch til-4 which closes a holding circuit to the relay 559 through conductor 2%, switch ADS-I, conductors 2235a, 2115b, switch 586-4, conductor 2&5, switch IIE, conductor 22m, relay 5G0 and conductors 258b, 288a and its to the other power line B. Thus, relay 588 will remain energized after the dog Hi2 of the finger-lift lever Z or dog IEEZ has released switch I96 and this switch has become opened. Relay 560, when so energized, also closes a switch 5i!i2, which energizes the solenoid of air valve 63 to deliver air under pressure to the right side of piston head 5! and shift the piston to the left to engage clutch 35, this circuit comprisin conductor 20'}, switch ASS-I, conductors 2535a, Ziifib, switch 535-4, conductor 1- 222, switch Hit-4, conductor 223 which leads to the solenoid of valve t3 and from thence the current passes through conductors 2080, 208b, 208a and 258: to the other power line B. Energizing solenoid 583 also closes a third switch 508-3, the closing of which energizes the magnet I26 of the timer T. Switch 559-4 is connected by conductors 22 and 225 to be inparallel with conductors 2,1,2 and H3 of the timer control switch 300-3, mentioned above in connection with the high speed control, and the'effect on the timer T by the closing of switch 596-3 is the same as the efiect-upon'the timer by closing of switch 3fiil3; andthe closing of either of these switches causes the timer to start running.

If the piston has been shifted sufliciently to make a complete engagement of clutch 36, the 'setscrew 58 will have moved far enough to open switch l'i lj, thus breaking the holding circuit to relay 538, causingv it to be ole-energized, thereby clutch 35, the: set screw 58 carried on the piston rod will not have moved far enough to open switch H 3, and, therefore, the. circuit to the timer If will-continue; closed and the timer will continue runninguntil it has run sufficiently long to close the switch 833, which upon closing will cause; the energization of relay 2% and the opening of the motor circuit switch tilt-4 in the manner previously described.

In the event there was a proper engagement of theclutch and; thetimer T did not energize safety relay liltl; there is no need of resetting or closing, switch iQii-l by breaking the holding circuit throughrelay 5,933- by opening contacts and HE of neutral switch it? (as this circuit is d-y open at liiiii-2) and the next operation be the closing or speed switch 165 to shift clutch throw lever 13.- to disengage clutch 3S and engage clutch- Si, whereby thecperation will-'be the same-- as above; described; or thenext operation could be the closing of contacts H38 and lfi oi neutral switch iii-l to effect movement offthe piston 51 and the clutch throw-lever 43 to neutral position. The latter operation of neutralswitch llllcompletes a circuit to the solenoid of 'valve 52 to cause the valve" to deliver air to theleit hand side of the piston head 5!, the circuit being from power line A through conductors 298,254, to switch terminal H38 and from 'switch'terminal Hi9 through conductors Z'Zilandf 22%, switch' 85, conductor 2290 to the solenoid of valve 62 and thence through conductorsttiid, 2986,?253817, 203a and ZQB to the other power" linB. When the piston. arrives atfneutral plc sitioh'plunger "l2 snaps cc of the enlargementjtfi on piston rod 52 and switch 8! opens, breaking the'circuit to the solenoid of valve}? and thus de energizing the solenoid relie'vingfthe cylinder o'fair pressure through exhaustflt. Inthe meantime contacts 188 and IBQ' of'neutral switch ifi'i will have been opened. 'From "the above; it is seen that pneumatic means are provide'd functioning under switch controlledelectric circuits to adjust either oi'the.

two" clutches of any change speed mechanism and, particularly in lathes, to establish or disestablishthe corresponding spindle speed or to I2 disengage both clutches to establish the drive through the gears ii and? IE, all at such times. and in the sequences desired, and either by the: manual operation of switches in the circuits orv bycperation of those switches by dogs carried" on the dog drum orwheel. of" the machine.

For: instance, andassuming that the main starter switch ST ofithe spindle motor circuitv has been operated, when the clutchv throw lever is. in neutral, the drive continues through low' speed gears ii and it until either high speed switch orlow' speed: switch is closed. The closing of'either or these switches operates the corresponding solenoid, valve 62- or 63 to operate the air cylinder piston to throw the clutch lever in the corresponding direction, the closing of established, this establishment of the speed automatically releases the air pressure from the clutch which otherwise will be held in engagement by detent D, or its equivalent, until again released by air pressure. Should the throw of the clutch lever itnot'be sufficient to establish.

a full engagement of either'clutch attempted to be. engaged, the. motor M, will be stoppedautomatically' aiter a" predetermined lengthf'off time byi'the' acti'onfoilth timer T'and all air pressure inthe air cylinder 59 is automatically released 1 therefrom. After. a. spindle drive or motor stops page, due to a failure to complete an attempted clutch engagementgthe drive or motor mayfbe restarted by operating switch It? either manuany or by a dog M3 on the. dog drum. Also by operating this switch It? the clutch lever (or other clutch actuating part) may be caused to shift from either speed drive through either clutch .iS'for 3-? to a neutral position or, as in the present showing, to a low drive adjustment while the spindle motor lVlfl is driving the change speed mechanism and. the spindle. ccording to the application of the invention as herein shown, the shift of the clutch lever may be also from a higher to a medium or from medium to high, orfrom either medium: or high to a still lower-speed, or from the lower speed to either high or medium speed- The simplicity, positivencss and safety of the control is apparent from the above description. With: such a. control for change-speed mechanism applied, as'depic'tedherein,. the speeds of the spindle of, a lathemay be changed While the workpiece is being operated on by the tools of the machine despite the fact that the dog drum is-necessarily rotated very slowly and the length of time during which the change-speed switches I05, Hifipr Hi? remain closed may be longer than the time required o i-the shipping of the clutches. Also upon the proper engagement of, either of the clutches or upon the return of the clutch motor. whenever an attempted engagement of either of the clutches does not take place properly Within the predetermined running time of the timer avoids wear on the clutches which would take place should the driving member of the clutch continue to rotate with a partial engagement with the driven clutch member. Furth r, it is apparent that, with the control described, it is possible to arrange for speed-changes of very short duration or for as long a period as desired. Other improvements and advantages will be readily apparent from the above to those skilled in the art.

Although certain specific embodiments of the invention, are shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims. For instance, the invention is applicable to single throw clutches or single coupling devices as well as double throw clutches or couplings and is equally applicable to the change speed mecha nism which effect changes in feed of machine tools.

That which is claimed, as new, is:

1. A combination with a power driven change speed transmission mechanism that is operated to effect change in speed by a power actuated shiftable member and wherein there is a controllable source of power for shifting said member, of a selectable control means connected with said shifting member to efiect its shifting movements and comprising a device connected to said source of power and positioned to be actuated at a pre-determined time by the movement of the shiftable member, when the latter is actuated to properly effect a change of speed of said inechanism, to release the power from said shiftable member, an operative connection between said device and the controllable power source f or shift ing said member, a second device connected to the power source of the change speed mechanism and operable to disconnect the mechanism from its power source when during a predetermined lapse of time from the time of initial speed changing actuation of said device a change of speed or" said mechanism has not been properly efiected.

2. In combination with a speed change transmission mechanism that is operated to efiect changes in speed by a shiftable member, a source of power for driving said mechanism connected thereto and a controllable power source for shifting said member connected thereto, a control means including initiating switches and electrical circuits therefor connected with said controllable power source for shifting said member; of an electrical switch element in the circuit of the initiating switch, which circuit effects movement of said member to change speed through said power source, said switch being positioned to be actuated at a pre-determined time by the movement of said shiftable member, when said change speed has been properly accomplished, to disconnect the controllable power source from said shiftable member, and a pre-set timer device in the circuit of said last mentioned initiating switch and set in motion thereby, said timer device including an operable means connected to the power source for driving said mechanism and to the controllable power source for shifting said member and actuated by the timer to disconnect said power source to the mechanism and the power source to said member.

3. A mechanism, as set forth in claim 2, fur

14 operable means to move to power connecting position, when said switch is actuated.

4. A mechanism, as set forth in claim 2, wherein the speed change mechanism includes a plurality of coupling members and there being one initiating switch and circuit therefor for effecting engagement of each coupling, respectively, andan initiating switch for effecting disengagement of said couplings, said coupling disengaging switch having a circuit connection to said operable means to maintain the latter, when actuated by the timer, in its power disconnecting position and when said switch is in its normal inoperative position, said coupling disengaging switch, when initially actuated, releasing said operable means to reset position and closing a circuit to said shiftable member power source to move said member in coupling disengaging position.

5. A control means for change speed transmission mechanism, which mechanism includes clutches to be engaged for changing speed, means for driving said mechanism and a power source for said drive means, said control means comprising a shiftable member movable in opposite directions to alternately engage and disengage said clutches and having a neutral position, a power operated device to shift said member, electric circuits for operating said power device including initiating switches therein selectively operable to effect said operations of said member, two normally closed switches in the circuit of the initiating switches which effect engagement of said clutches and each positioned to be actuated, respectively, by said member, when moved in opposite directions to open its circuit and said member fully efiects engagement of one of said clutches, a preset timer in the circuits of the initiating switches which cause engagement of said clutches and actuated thereby when either of said circuits is closed, a relay circuit controlled by the timer and a relay in said relay circuit operating a holding circuit controlling said power source to said drive means and to said power operated device, said holding circuit being operated by said timer to render said drive means and said power operated device inefiective when said power operated device fails to open said normally closed switches.

6. A control, as set forth in claim 5, wherein another of said initiating switches is in a holding circuit to said relay and normally maintains said circuit, when said holding circuit is operated by said timer, and breaks said holding circuit when actuated, whereby said holding circuit reestablishes power to said drive means of said mechanism and to said power device of said shiftable member.

7. In combination with a power driven change speed transmission mechanism that is operated to eiTect change in speed by a power actuated shiftable member and wherein there is a controllable source of power for shifting said member selectively to a neutral or to one or the other of two opposed operative positions, of a selectable control means connected with said shifting member to effect its shifting movements to neutral or operative positions, wherein the control means includes a pro-set timer, a connection between said control means and said timer for setting the timer in operation when said shiftable member is actuated to effect a change of speed of said mechanism, a power drive to said mechanism, and a power cut-off means actuated by said timer after a predetermined lapse of time, to cut assesses position to-estab1ish a second speed setting in W said change speed mechanism andv shiftable intoa third neutral position, and power means f'or. driving the change speedmechanism, said control including, in combination, a power operated dejvice'connected to said change speed adjusting 5 w,

member and operable to shift said member to each of saidthreepositions, a source of power for operating said power operated device, elec'= trically operated control devices and electrica'la circuits therefor controlling the supply of power to said power means and to said power device, said circuits including control initiating-"switches' therein whereby said controldevices-are operatedi to pass power from said power'source toipower." means to drive said'mechanism and to passip'oweri to-saidi-power operatedidevice to shift said change speed adjustment member'to each ofsaid three positions,- said electrical circuits i including s'afe'ty switches therein to be actuated by said. power 116 operated device, w-hen'moved'to its first and-sec ond positions, for relieving p'ower from said power: operated device, and a pre-set timingidevic'e cone nected incsaidl circuits controllin'g'said poweroperated device and set in motion by'the initiating. switches for the first and second positionsof said power operated device, a power-controllercontrolling power from said source to said'=' power means: that drives: said mechanism and to:- saidpower operated device; said power controller'being actuated by the timing device; after apre -settime' lapse and upon"- the failure of said power operated device to place said" adjustingmember. properly in any of' said first or second positions, to cut out said power to said drivem'e'ans and? to saidipowenoperat'ed device.-

HAROLIIB. SOULEQ GORDON \V'. SMITHSONL REFERENCES CITE D The following; references are of record insthe' file of this patent:

UN I'TED STATES PATENTS Number: Name, Date" 2,234,463 Brewer Mar: 11, 1941" 2,266,598 Hale Dec. 16,1941 2,357,396 Fuller Sept: 5, 1944 

